U.S. patent number 10,072,748 [Application Number 15/098,695] was granted by the patent office on 2018-09-11 for axle oil flow controller on pinion spacer.
This patent grant is currently assigned to SCHAEFFLER TECHNOLOGIES AG & CO. KG. The grantee listed for this patent is Schaeffler Technologies AG & Co. KG. Invention is credited to Stephen Carr, Shaun Tate.
United States Patent |
10,072,748 |
Carr , et al. |
September 11, 2018 |
Axle oil flow controller on pinion spacer
Abstract
A differential assembly arrangement with optimized pinion shaft
bearing lubrication is provided. The assembly includes a housing, a
ring gear, a pinion gear, a pinion shaft supported by two rolling
element bearings, a sleeve, and a lubrication deflector. The two
rolling element bearings, a pinion head bearing bearing and a
pinion tail bearing, are located at each end of the sleeve which
fits over the pinion shaft. The sleeve helps facilitate the
application of a pre-load to the bearings. The lubrication
deflector is located along the length of the sleeve for providing
the correct amount of lubricant to the two bearings. The deflector
is in the form of a ring located on the sleeve or integrated within
the sleeve.
Inventors: |
Carr; Stephen (Waterford,
MI), Tate; Shaun (Grand Blanc, MI) |
Applicant: |
Name |
City |
State |
Country |
Type |
Schaeffler Technologies AG & Co. KG |
Herzogenaurach |
N/A |
DE |
|
|
Assignee: |
SCHAEFFLER TECHNOLOGIES AG &
CO. KG (Herzogenaurach, DE)
|
Family
ID: |
59980666 |
Appl.
No.: |
15/098,695 |
Filed: |
April 14, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20170299044 A1 |
Oct 19, 2017 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16H
57/0483 (20130101); F16H 48/42 (20130101); F16H
57/042 (20130101); F16H 2048/423 (20130101) |
Current International
Class: |
F16H
57/04 (20100101); F16H 48/42 (20120101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Scott; Jacob S
Attorney, Agent or Firm: Volpe and Koenig, P.C.
Claims
What is claimed is:
1. A differential assembly comprising: a housing defining a port; a
ring gear disposed within the housing; a pinion shaft disposed
within the housing having a pinion gear located on a first end of
the pinion shaft for engaging the ring gear; a pinion head bearing,
proximate to the pinion gear, for supporting the pinion shaft with
respect to the housing; a pinion tail bearing for supporting the
pinion shaft with respect to the housing, the port of the housing
defining a lubricant outlet between the pinion head bearing and the
pinion tail bearing; a sleeve disposed on the pinion shaft with a
first end in contact with the pinion head bearing and a second end
in contact with the pinion tail bearing; and a deflector, disposed
on the sleeve for regulating a flow of lubricant to the pinion tail
bearing and the pinion head bearing, the deflector being axially
offset from the lubricant outlet.
2. The differential assembly of claim 1, wherein the deflector
material is metal.
3. The differential assembly of claim 1, wherein the deflector
material is at least one of a plastic or an elastomer.
4. The differential assembly of claim 1, wherein the deflector is
formed as a ring extending radially outwardly from the sleeve.
5. The differential assembly of claim 1, wherein the housing has a
protrusion located opposite to the deflector, and the protrusion
and the deflector are radially co-planar.
6. The differential assembly of claim 5, wherein a spacing between
a distal end of the protrusion of the housing and a distal end of
the deflector is set to adjust an amount of lubricant flow to the
pinion head bearing and the pinion tail bearing.
7. The differential assembly of claim 4, wherein there are a
plurality of rings.
8. The differential assembly of claim 1, wherein the deflector is
formed integrally with the sleeve.
9. The differential assembly of claim 8, wherein the deflector is
formed as a radially outwardly directed protrusion of a wall of the
sleeve defining two outwardly extending rings having a space of at
least 0.02 mm located therebetween.
10. The differential assembly of claim 9, wherein a wall thickness
of the two outwardly extending rings is less than or equal to a
thickness of a remainder of the sleeve wall.
11. The differential assembly of claim 10, wherein the radially
outwardly directed protrusion is axially compressible to pre-load
the pinion head bearing and pinion tail bearing.
12. The differential assembly of claim 11, wherein the radially
outwardly directed protrusion is axially elastically
compressible.
13. An oil flow regulator for a pinion shaft of a differential
assembly for regulating lubricant flow to a pinion tail bearing and
a pinion head bearing, the oil flow regulator comprises a sleeve
adapted to extend between the pinion head bearing and pinion tail
bearing; and an annular ring with a radially extending lip located
at a medial position on the sleeve, such that the lubricant flow to
the tail bearing is greater than to the head bearing.
14. The oil flow regulator of claim 13, wherein the regulator
material is metal.
15. The oil flow regulator of claim 13, wherein the regulator
material is at least one of a plastic or an elastomer.
16. The oil flow regulator of claim 13 further comprising a second
annular ring, the two annular rings being formed a radially
outwardly directed protrusion of a wall of the sleeve having a
space of at least 0.02 mm located therebetween.
17. The differential assembly of claim 16, wherein a wall thickness
of the two annular rings is less than or equal to a wall thickness
of a remainder of the sleeve wall.
18. The differential assembly of claim 17, wherein the radially
outwardly directed protrusion is axially compressible to pre-load
the pinion head bearing and the pinion tail bearing.
19. The differential assembly of claim 18, wherein the outwardly
directed protrusion is axially elastically compressible.
Description
BACKGROUND
The present invention relates to a differential assembly, and more
particularly, to the lubrication of the rolling element support
bearings for the pinion shaft of the differential assembly.
Differential assemblies are well known and arranged in the drive
train system of a motor vehicle to allow a pair of output shafts,
operatively coupled to an input shaft, to rotate at different
speeds. As the output shafts are connected to the wheels of the
vehicle, this function is required to allow the outer drive wheel
to rotate faster than the inner drive wheel while the vehicle is
turning. Differential assemblies utilize rolling element bearings
to support the pinion shaft which provides rotational input to the
output shafts.
Rolling element bearings require lubrication to keep the bearing
components cool and maintain a required lubrication film thickness,
both of which are required to meet bearing lifetime requirements.
Excessive lubrication can be detrimental and impose a drag, termed
as churning losses, on the rolling element bearing, resulting in an
undesirable increase in friction.
Referring to FIG. 1, a cross-sectional view of a prior art
differential assembly is shown. The differential assembly 100
contains a housing 102 along with a ring gear 104, a pinion shaft
106 and a pinion gear 108. The pinion shaft is supported by a
pinion head bearing 110 and a pinion tail bearing 112. A sleeve 114
abuts against the respective inner rings of the two bearings,
assisting with applying the necessary pre-load for optimum
operating clearance purposes. The differential housing contains
lubricant to a level L, resulting in portions of the pinion gear
108, the ring gear 104, the pinion head bearing 110 and the pinion
tail bearing 112 being immersed in lubricant when the vehicle is on
level ground. The pinion shaft 106 provides rotational input to the
ring gear 104 via the pinion gear 108. As rotation and subsequent
meshing of the gears occurs, oil is splashed within the housing
102. The splash lubricant follows a path through a port 116
indicated by the arrows to reach the space between the bearings,
providing both bearings 110, 112 with lubricant. This path of oil
is particularly vital to the pinion tail bearing 112 during low
lubricant level conditions or when the vehicle is travelling
downhill and the lubricant moves away from the tail bearing. Due to
the proximity of the pinion head bearing 110 to the pinion gear
108, the pinion head bearing 110 receives splash lubrication from
the pinion gear interface with the ring gear 104. Therefore, the
pinion head bearing 110 receives lubrication from both sides,
exceeding the amount of lubrication provided to the pinion tail
bearing 112 during most operating conditions and oil level
conditions. In order to ensure adequate lubrication is delivered to
the pinion tail bearing, the port 116 must be arranged to capture
and direct enough lubricant to ensure that the lifetime requirement
of the pinion tail bearing 112 is met during the worst case
lubrication conditions. The disadvantage of this strategy is that
excessive lubrication is provided to the pinion head bearing 110
which yields higher bearing friction due to churning losses. It is
necessary to provide adequate, but not excessive lubrication to
both of the bearings for optimum efficiency of the differential
assembly.
SUMMARY
A differential assembly arrangement with optimized pinion shaft
bearing lubrication is provided. The assembly includes a housing, a
ring gear, a pinion gear, a pinion shaft supported by two rolling
element bearings, a sleeve, and a lubrication deflector. The two
rolling element bearings in the form of a pinion head bearing and a
pinion tail bearing are located at each end of the sleeve which
fits over the pinion shaft. The sleeve helps facilitate the
application of a pre-load to the bearings. The lubrication
deflector is located along the length of the sleeve for providing
the correct amount of lubricant to the two bearings. Preferably,
the deflector is made of metal but can also be made of plastic or
an elastomer.
In one embodiment, the deflector is in the form of a ring or
multiple rings that project away from the sleeve. More than one
ring is possible. The amount of lubrication that flows past the
deflector is a function of the projection length of the ring in
addition to the axial location of the ring along the sleeve. In
another aspect, a protruding feature on the housing opposite the
ring works together with the deflector to regulate the flow of
oil.
In another embodiment, the sleeve and deflector are integrally
formed as one component. In another aspect, the shape of the
protruding deflector provides for an added elastic characteristic;
thereby, the sleeve and deflector combination can be used as a
spring-like component to provide pre-load to the bearings.
In another arrangement an oil flow regulator for the bearings of a
pinion shaft or other shaft can be used separately from a
differential assembly to provide the proper amount of lubrication
to each of the two bearings. Preferably the regulator is made of
metal, but can also be made of plastic or an elastomer. As within
the differential assembly, an additional embodiment integrates the
sleeve and deflector into one component, with an additional aspect
including a spring-like characteristic.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing Summary as well as the following Detailed Description
will be best understood when read in conjunction with the appended
drawings. In the drawings:
FIG. 1 is a cross-sectional view of a prior art differential
assembly.
FIG. 2 is a cross-sectional view of a differential assembly with a
first embodiment of a deflector.
FIG. 3 is an enlarged portion of the cross-sectional view of the
differential assembly of FIG. 2.
FIG. 4 is a cross-sectional view of a variation of the first
embodiment of the deflector shown in FIG. 2.
FIG. 5 is a cross-sectional view of a second embodiment of a
deflector.
FIG. 6 is a cross-sectional view of a variation of the second
embodiment of the deflector shown in FIG. 5.
FIG. 7 is a cross-sectional view of another variation of the second
embodiment of the deflector.
FIG. 8 is a cross-sectional view of a further variation of the
second embodiment of the deflector.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Certain terminology is used in the following description for
convenience only and is not limiting. The words "inner," "outer,"
"inwardly," and "outwardly" refer to directions towards and away
from the parts referenced in the drawings. A reference to a list of
items that are cited as "at least one of a, b, or c" (where a, b,
and c represent the items being listed) means any single one of the
items a, b, c or combinations thereof. The terminology includes the
words specifically noted above, derivatives thereof, and words of
similar import.
Referring to FIGS. 2 and 3, a differential assembly 10 with a first
embodiment of a deflector 26 to guide and regulate the oil flow to
the pinion shaft bearings is shown. The differential assembly 10
includes a housing 12, a ring gear 14, a pinion shaft 16 and a
pinion gear 18. The pinion shaft 16 is supported by two bearings, a
pinion head bearing 20 and a pinion tail bearing 22. One that is
skilled in the art of differentials would understand from the
present disclosure that each of these bearings could be in the form
of any rolling element bearing; examples include tapered roller,
angular contact ball, and tandem ball bearings. The deflector 26
directs and regulates the amount of oil that flows to the pinion
head bearing 20, such that most of the splash oil that flows
through a port 28 formed in the housing is fed to the pinion tail
bearing 22. In this embodiment the deflector 26 is integrated with
sleeve 24 to reduce the number of components. Potential materials
for this component include, but are not limited to, metal and
plastic. Multiple design facets permit different lubrication flow
rates to the pinion head bearing 20 which include, but are not
limited to, deflector height h and deflector axial position along
the length of the sleeve 24. In a preferred aspect of this
embodiment, the housing 12 further includes a housing protrusion 30
located opposite to the deflector 26. As shown in FIG. 3, distance
y, which defines the opening between the housing protrusion 30 and
the deflector 30, is another design facet that will affect the
lubrication flow rate to pinion head bearing 20. Preferably, this
distance ranges from 1 to 25 mm, however, the distance y can vary
depending on the particular application.
Referring now to FIG. 4, a variation of the first embodiment of the
sleeve 24' is shown that includes an integral deflector 26'. The
deflector 26' is integrated as a u-shaped radial protrusion formed
in a wall of the sleeve 24' that defines two radially extending
rings 28', with a space between the rings 28' denoted as x, which
adds a spring-like characteristic to the sleeve 24'. Preferably,
the minimum space defined by x is 0.02 mm. This sleeve 24' captures
an additional function as a bearing pre-load device, often termed
as a "crush ring" to those familiar in the art. The preferred
material is metal with a protrusion wall thickness that is equal to
or less than the wall thickness of the remainder of the sleeve 24'.
In one preferred embodiment, the thickness of the sleeve 24' is 0.5
to 4 mm.
FIG. 5 shows a second embodiment of a deflector 36 in the form of a
radially extending ring 38 that is located on the circumference of
the sleeve 34. Preferably, the material of the ring is metal or
plastic. The deflector 36 can include an axially extending flange
40 for mounting on the sleeve 34.
FIG. 6 shows another variation of the second embodiment of the
deflector 36' in the form of a radially extending ring 38' that is
located on the circumference of the sleeve 34'. Preferably, the
material is metal or plastic. The deflector 36' can include an
axially extending flange 40' which in this variation forms a
"T"-shaped cross-section with the ring 38' that provides additional
support for the ring 38' as well as a mounting surface for
connection to the sleeve 34'.
FIG. 7 is a further variation of the second embodiment of a
deflector 36'' that includes two radially extending rings 38'' that
are located on the circumference of the sleeve 34''. These are
supported on an axially extending flange 40'' that allows mounting
on the sleeve 34''. Quantities of protruding rings that are greater
than two are possible within one deflector. Preferably, the
material is metal or plastic. This arrangement can function in
connection with the protrusion 30 shown in FIGS. 2 and 3 to form a
resistive path in order to further limit lubricant flow to the
pinion head bearing 20.
FIG. 8 is yet another variation of the second embodiment of a
deflector 36''' in the form of an elastomeric ring arrangement
38''' that is formed of an elastomeric material that is integrated
with a metal flange 40''' that allows for mounting on the
circumference of the sleeve 34'''.
The deflectors 36, 36', 36'', 36''' can be mounted by an adhesive,
or interference fit, or a weld to the sleeve 34, 34', 34'',
34'''.
Having thus described various embodiments of the present bearing
arrangement in detail, it is to be appreciated and will be apparent
to those skilled in the art that many physical changes, only a few
of which are exemplified in the detailed description above, could
be made in the apparatus without altering the inventive concepts
and principles embodied therein. The present embodiments are
therefore to be considered in all respects as illustrative and not
restrictive, the scope of the invention being indicated by the
appended claims rather than by the foregoing description, and all
changes which come within the meaning and range of equivalency of
the claims are therefore to be embraced therein.
* * * * *